Method of protecting resisters of electric furnaces.



P. A. J. FITZ GERALD. I METHOD OF PROTECTING RESISTERS 0F ELECTRIC FURNACES.

APPLICATION FILED SEPT. 1,1909.

Patented Mar. 1, 1910.

A7TORNEY6 WITNESSES kn-r7! I 5mm 0%.

UNITED stratus PATENT orrroa.

rnancrs A. J. riTzeERALi), or NIAGARA FALLS, NEW YORK, ASSIGNOR 'IO IMBERT rnocnss COMPANY, OF NEW YORK, 1v. Y., A CORPORATION OF NEW YORK.

METHOD OF PROTECTING RESISTERS 015 ELECTRIC FURNACES.

Specification of Letters Patent.

Patented Mar. 1, 1910.

Application filed September 1, 1909. Serial No. 515,711.

To all whom "it may concern:

Be it known that I, FRANCIS A. J. Frrz GERALD, a subject of the King of Great Britain, and a resident of Niagara Falls, in the county of Niagara and State of New York, have invented certain new and useful Improvements in Methods of Protecting Resisters of Electric Furnaces, of

which the following is a specification, reference being had to the accompanying drawings, forming a part hereof.

The object of the invention is to effectively prevent the entrance of air into the heating or melting chamber of electric furnaces, or around the resister, for the purpose of protecting the latter from the detrimental effects of the contained oxygen and thus enhancing the endurance and efliciency of the resister.

It is well known that where carbon resisters are employed in electric furnaces, the effect of the presence of air and other active gases in the melting chamber, where the resister is exposed, is to actively attack and disintegrate the carbon. For this reason, it is particularly desirable to have some method of checking the action of the gases upon the carbon; and the present invention, broadly considered, contemplates the introduction, more or less continuously, of an inert gas, such as producer gas, into the melting chamber around the resister, such gas largely displacing any active gas which may have been generated therein and elfectively checking the entrance of air. More- OVQI' in accordance with the invention, the introduction of inert gas may be controlled manually, as visual observation may dictate, or automatically according to the relation of pressures within and. without; or, in fact, the inert gas may be delivered gradually to the furnace substantially without interruption. I

Referring to the drawings: Figure 1 shows, in vertical section, an electric furnace provided with means for practicing the invention, and, Fig. 2 is also a sectional view, showing a form of regulating or controlling means which may be used in carrying out the invention.

In Fig. 1, the carbon resister is shown at D, having terminals 6 and e and disposed above the bath in the melting chamber 0. The furnace, in the present instance, is provided with a cover I) and a charging opening 9. The inert gas may be forced in through a refractory tube or opening m and the amount of gas introduced may be regulated by any suitable means until sufiicient gas enters to maintain a test flame, as through a duct n in the cover I). The quantity of gas necessary to thus exclude the air is, as to its cost, commercially negligible; and ordinarily, the rate of its delivery will vary according to conditions. Thus, in first starting a. furnace, raising the temperature from normal to high, or when opening the furnace for inspection or charging, the quantity will be maximum, whereas when the internal heat-pressure exceeds that of the external air-pressure no gas whatever would be required.

Advantage can ,be taken of the foregoing conditions to regulate or control the supply of inert gas automatically. Thus, as in Fig. 2, a check valve may be provided in the delivery tube which shall comprise the following elements: A main casing-1, having a sulta-ble head 2 in which is a cross strut 3 acting as a bearing for a spindle 4 of a puppet valve h, preferably formed with a conical contact surface 5'to impinge upon a corresponding surface 6 formed within the casing. In the position assumed in the drawing, the valve is open, leaving a narrow circumferential space, as 7, which connects the chamber 8 with the chamber 9. The area of the valve .should be relatively large as compared with that of the connecting pipes. Now, if the inert gas enters in the direction of the arrow, it will pass around the circumferential opening of the valx e and thence to the furnace; but if the heat-pressure from the furnace exceeds that of the as, then the fiow will be reversed, and the valve will be forced to its seat, as indicated in dotted lines 10, while the heat-flow will terminate in the valve chamber. The axis ofthe valve is preferably set at an angle to the horizontal, as shown, so that the valve will, by gravity, remain open. Obviousl this condition may be neutral or reversed, ut the object of the disposal shown is to insure an immediate flow, or as it were, a sli ht static head, of the inert gas to or in the mace chamber.

It has been ascertained by practical demonstration that the method herein described durance and efliciency of electric carbon resisters can thus be increased to an extent not hitherto deemed possible. While it is manifest that a small amount of carbon monoxid gas will result from the introduction of the producer gas, this Will be far less harm- Ital, even in the most delicate of commercial metallurgical operations, than the oxygen or the carbon dioxid gas which would otherwise ordinarily be present.

l claim as my invention:

The method of protecting the resister of an electric furnace from oxidizing or other active gases which consists in introducing an inert gas into the melting chamher and around the resistor.

52. The method of protecting the resister of an electric furnace from oxidizing or other active gases, which consists insurrounding the resister with an inert gas.

.- )v' r A 4 .5; lhc method of protecting the resistor 01' an electric furnace from oxidizing or other actlve gases, \VlllCll consists in introdueing an inert gas continuously into the melting chamber and around the resistor.

4. The method of protecting the rcsister according to the pressure in the melting chamber.

Thls specification signed and witnessed this 26th day of August, 1)., 1909.

FRANCIS A. J. FITZ GERALD.

Signed in the presence of-'- D. R. MILLER, I P. MON. BENNIE. 

